The relevance of the Cabinet has declined in recent decades, following strong leadership from No 10 from Margaret Thatcher and Tony Blair. Yesterday a document published by the Cabinet Office revealed the full extent of the reliance the coalition government is likely to place on the institution.

"The Cabinet is the supreme decision-making body in government, dealing with the big issues of the day and the government's overall strategy," it read.

"Cabinet committees reduce the burden on Cabinet by enabling collective decisions to be taken by a smaller group of ministers. The composition and terms of reference of coalition Cabinet committees are a matter for the prime minister, in consultation with the deputy prime minister."

As a result of the committee decisions Mr Clegg will be able to contribute to policy discussions on reshuffles, policy disputes and even influence the Budget.

The Lib Dems have strength in depth across the Cabinet committees, holding at least the deputy chair positions.

Business secretary Vince Cable is the deputy chair on the economic affairs committee and the banking reform committee.

Energy and climate change secretary Chris Huhne is the deputy chair of the European affairs committee; chief secretary to the Treasury David Laws is Iain Duncan Smith's number two on the social justice committee; and David Heath deputises for Sir George Young on the parliamentary business and legislation committee.

Justice secretary Ken Clarke will be the deputy chair on Mr Clegg's home affairs committee.